scholarly journals Modified Potentiometric Screen-Printed Electrodes Based on Imprinting Character for Sodium Deoxycholate Determination

Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 251 ◽  
Author(s):  
Ayman H. Kamel ◽  
Samar Ezzat ◽  
Mona A. Ahmed ◽  
Abd El-Galil E. Amr ◽  
Abdulrahman A. Almehizia ◽  
...  

Potentiometric sensors have a great influence on the determination of most various compounds in their matrices. Therefore, efficient and new sensors were introduced to measure sodium Deoxycholate (NaDC) as a bile acid salt. These sensors are based on NaDC imprinted polymer (MIP) as sensory element. The MIP beads were synthesized using thermal polymerization pathway, in which acrylamide (AAm), ethylene glycol dimethacrylate (EGDMA), NaDC, and benzoyl peroxide (BPO) were used as the functional monomer, cross-linker, template, and initiator, respectively. The proposed sensors were fabricated using a coated screen-printed platform and the sensing membrane was modified by single-walled carbon nanotubes (SWCNTs) as an ion-to-electron transducer. The sensors exhibited high sensitivity that reached 4.7 × 10−5 M of near-Nernestian slope (−60.1 ± 0.9 mV/decade, r2 = 0.999 (n= 5)). In addition, the sensors revealed high selectivity, long lifetime, high potential stability, and conductivity that ensure reproducible and accurate results over a long time. MIP characterization was performed using Fourier Transform-Infrared (FT-IR) and a scanning electron microscope (SEM). Regarding the interaction of NaDC with serum albumin (SA), albumin is determined in human serum samples as human serum albumin (HSA), which was collected from different volunteers of different ages and gender.

2007 ◽  
Vol 2 ◽  
pp. 117727190700200 ◽  
Author(s):  
Ziad J. Sahab ◽  
Suzan M. Semaan ◽  
Qing-Xiang Amy Sang

Biomarkers are biomolecules that serve as indicators of biological and pathological processes, or physiological and pharmacological responses to a drug treatment. Because of the high abundance of albumin and heterogeneity of plasma lipoproteins and glycoproteins, biomarkers are difficult to identify in human serum. Due to the clinical significance the identification of disease biomarkers in serum holds great promise for personalized medicine, especially for disease diagnosis and prognosis. This review summarizes some common and emerging proteomics techniques utilized in the separation of serum samples and identification of disease signatures. The practical application of each protein separation or identification technique is analyzed using specific examples. Biomarkers of cancers of prostate, breast, ovary, and lung in human serum have been reviewed, as well as those of heart disease, arthritis, asthma, and cystic fibrosis. Despite the advancement of technology few biomarkers have been approved by the Food and Drug Administration for disease diagnosis and prognosis due to the complexity of structure and function of protein biomarkers and lack of high sensitivity, specificity, and reproducibility for those putative biomarkers. The combination of different types of technologies and statistical analysis may provide more effective methods to identify and validate new disease biomarkers in blood.


Biosensors ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 88 ◽  
Author(s):  
Nan Li ◽  
Ari M. Chow ◽  
Hashwin V. S. Ganesh ◽  
Melanie Ratnam ◽  
Ian R. Brown ◽  
...  

Altered growth hormone (GH) levels represent a major global health challenge that would benefit from advances in screening methods that are rapid and low cost. Here, we present a miniaturized immunosensor using disposable screen-printed carbon electrodes (SPCEs) for the detection of GH with high sensitivity. The diazonium-based linker layer was electrochemically deposited onto SPCE surfaces, and subsequently activated using covalent agents to immobilize monoclonal anti-GH antibodies as the sensing layer. The surface modifications were monitored using contact angle measurements and X-ray photoelectron spectroscopy (XPS). The dissociation constant, Kd, of the anti-GH antibodies was also determined as 1.44 (±0.15) using surface plasmon resonance (SPR). The immunosensor was able to detect GH in the picomolar range using a 20 µL sample volume in connection with electrochemical impedance spectroscopy (EIS). The selectivity of the SPCE-based immunosensors was also challenged with whole blood and serum samples collected at various development stages of rats, demonstrating the potential applicability for detection in biological samples. Our results demonstrated that SPCEs provided the development of low-cost and single-use electrochemical immunosensors in comparison with glassy carbon electrode (GCE)-based ones.


2019 ◽  
Vol 43 (46) ◽  
pp. 17937-17940 ◽  
Author(s):  
Zideng Gao ◽  
Shunyi Wang ◽  
Zijun Xu ◽  
Jin Liu ◽  
Yuanfang Huang ◽  
...  

Novel cationic carbon dots were synthesized in a simple way and applied to detect K+ in human serum samples with ultra-high sensitivity.


2017 ◽  
Vol 118 ◽  
pp. 25-30 ◽  
Author(s):  
Sagarika Deepthy Tallapragada ◽  
Keya Layek ◽  
Runu Mukherjee ◽  
Kalyan Kumar Mistry ◽  
Monidipa Ghosh

Author(s):  
Carl Jenkinson ◽  
Reena Desai ◽  
Andrzej T. Slominski ◽  
Robert C. Tuckey ◽  
Martin Hewison ◽  
...  

Abstract Objectives Clinical evaluation of vitamin D status is conventionally performed by measuring serum levels of a single vitamin D metabolite, 25-hydroxyvitamin D predominantly by immunoassay methodology. However, this neglects the complex metabolic pathways involved in vitamin D bioactivity, including two canonical forms D3 and D2, bioactive 1,25-dihydroxy metabolites and inactive 24-hydroxy and other metabolites. Methods Liquid chromatography-tandem mass spectrometry (LC-MS/MS) can measure multiple analytes in a sample during a single run with high sensitivity and reference level specificity. We therefore aimed to develop and validate a LC-MS/MS method to measure simultaneously 13 circulating vitamin D metabolites and apply it to 103 human serum samples. Results The LC-MS/MS method using a Cookson-type derivatization reagent phenyl-1,2,4-triazoline-3,5-dione (PTAD) quantifies 13 vitamin D metabolites, including mono and dihydroxy-metabolites, as well as CYP11A1-derived D3 and D2 metabolites in a single run. The lower limit of quantitation was 12.5 pg/mL for 1,25(OH)2D3 with accuracy verified by analysis of National Institute of Standards and Technology (NIST) 972a standards. Quantification of seven metabolites (25(OH)D3, 25(OH)D2, 3-epi-25(OH)D3, 20(OH)D3, 24,25(OH)2D3, 1,25(OH)2D3 and 1,20S(OH)2D3) was consistently achieved in human serum samples. Conclusions This profiling method can provide new insight into circulating vitamin D metabolite pathways forming the basis for improved understanding of the role of vitamin D in health and disease.


Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5298 ◽  
Author(s):  
Lee ◽  
Sung ◽  
Kang ◽  
Parameswaran ◽  
Choi ◽  
...  

The level of human serum albumin (HSA) in biological fluids is a key health indicator and its quantitative determination has great clinical importance. In this study, we developed a selective and sensitive fluorescent HSA probe by fluorescence-based high-throughput screening of a set of fluorescent thieno[3,2-b]pyridine-5(4H)-one derivatives against major plasma proteins: HSA, bovine serum albumin (BSA), globulin, fibrinogen, and transferrin. The fluorophore chosen finally (4 in Scheme 1) showed noticeable fluorescence enhancement in the presence of HSA (160-fold increase), and it exhibited rapid response, high sensitivity (detection limit 8 nM), and the ability to clearly distinguish HSA from BSA in pH 9 buffer condition. Moreover, the probe could be applicable to detect trace amounts of HSA in an artificial urine sample; further, it might be applied to the determination of the HSA concentration in complex biological samples for pre-clinical diagnosis.


2021 ◽  
Author(s):  
Chun-Yao Huang ◽  
Chi-Jung Chang ◽  
Bohr-Ran Huang ◽  
Chien-Hsing Lu ◽  
jemkun chen

Abstract Background: Separation of macromolecules or particles from a colloid system to from gradient structure on the surface has been employed for biosensing systems, suggesting an enhancement of the chemical and physical features of particles. Performance of an electrochemiluminescence (ECL) immunosensor was employed to improve with a particle gradient.Results: Magnetic beads with silicon dioxide coating were adopted as nanocarriers for gradient manipulation and immobilized with the primary antibody. Cadmium telluride quantum dots (CdTe QDs) were coated with a layer of protein G for conjugation and orientation of secondary antibody as signal labels. ECL immunosensor gradients upon the electrode were formed by magnetolithography with magnetized nickel masks of column and stripe arrays at various scales. The immunosensor generally aggregated as island on the substrate through a dry process of water evaporation leading to a decrease of efficiency in the characteristic signals. Stripe arrays of magnetized nickel were designed to generate cylindrical magnetic flux on the substrate to improve the particle manipulation with the gradient. Various gradients of the sandwich-structured immunosensor substantially affected the electrochemical performance. Compared to the gradient-free immunosensor, the gradient of the immunosensor generated using the 3-μm-stripe array mask of magnetolithography enhanced the ECL intensity ~2.2 times. Conclusions: The results of quantification of human serum albumin (HSA) with the gradient immunosensor showed a broad linear range (15–420 ng mL−1), a low limit of detection (8 ng mL−1) and high reliability for HSA-spiked serum samples, indicating that the immunosensor gradient substantially enhances the performance of the ECL assay.


2013 ◽  
Vol 718-720 ◽  
pp. 552-556
Author(s):  
Qing Ye Liu ◽  
Hao Ying Zhai ◽  
Ai Hui Liang

In suitable pH value of Walpole buffer solution and in the presence of surfactant Triton X-10 and alcohol, PtCl62- reacts with I- to form PtI62-. By means of the electrostatic and hydrophobic forces, proteins with positive charge, such as human serum albumin (HSA), bovine serum albumin (BSA), human immunoglobulin (IgG) and ovalbumin (OVA), associates with PtI62- to form stable [protein-(PtI6)n]m association particles which cause substantial enhancement of Rayleigh scattering and interface fluorescence. They produce three Rayleigh scattering peaks at 330 nm, 420 nm and 464 nm and a resonance scattering peak at 580 nm, among which the strongest peak is at 464 nm. The four kinds of protein association particle system all exhibit a strong fluorescence peak at 466 nm, while the HSA fluorescence peak at 360 nm was quenched with the formation of the association particle. The cause of the Rayleigh scattering peaks of the association particle system was considered in detail, and the relationship between the Rayleigh scattering and fluorescence of the association particle (the means diameter is about 470 nm) and the fluorescence quenching of HSA was interpreted. Under the optimal experimental conditions, there is a good linear relationship between the scattering intensity (I464 nm) and protein concentration in the range of 0.05~25μg/mL HSA, 0.05~25μg/mL BSA, 0.3~30μg/mL IgG and 0.1~16μg/mL OVA respectively, with a detection limit of 20 ng/mL HSA, 26 ng/mL BSA, 40 ng/mL IgG and 70 ng/mL OVA. This assay has been applied to the determination of the albumin of human serum samples with satisfactory results.


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